1. Field of the Invention
The present invention relates to a computer system having a function of executing a sleep mode as a power saving mode.
2. Description of the Related Art
Of the conventional computer systems such as personal computers, some computers are designed such that a sleep mode (power saving mode) is set when no key input is made from the keyboard within a predetermined period of time while the CPU is in an idle state. In the sleep mode, the frequency of a clock supplied to the CPU is decreased to set the operating speed of the CPU in a low speed mode. With this operation, the overall power consumption of the system can be reduced.
The sleep mode is normally controlled by the BIOS (basic input/output system) of the system. The BIOS checks a key code input from the keyboard, and sets the sleep mode if no key code is present in the buffer. However, some application software uses the key code read function of the BIOS. In this case, the sleep mode cannot be executed.
In the conventional systems having the sleep mode, even if no key input is made from the keyboard during the execution of application software, the sleep mode cannot be executed sometimes.